Good Drainage Planes stop Capillary Action

We use drainage gaps or planes in wall systems to stop water from entering the building shell and causing deterioration or mould. This air gap does two things if wide enough; it prevents water’s surface tension from staying or even climbing up the wall and the gap also disperses the forces of wind driven rain or solar vapour drive. Let’s look at two common issues that may cause problems in the near future.

When dimpled membranes were first introduced on the market, manufacturers were quite explicit about the need to fasten the top edge of the membrane with a terminal strip. They still are!

The goal of a dimpled membrane is to create and air pocket between the concrete foundation wall and the membrane itself with the aim of allowing any water that get’s past the membrane to quickly fall down the air pocket to the footing drain. The beauty of the system is that it stops the forces of capillary action that might normally hold the water against the wall. In order to stop the forces of capillary action, you need an open clear gap though.

The strip plays an important role in preventing debris from falling into and filling that precious air gap. Its uncommon to see terminus strips installed on most job sites, but this is an easy fix; follow the manufacturer’s instructions!